Domenico Praticò, MD, Professor in the Departments of Pharmacology and Microbiology and Director of the Alzheimer's Center at the Lewis Katz School of Medicine at Temple University, as well as senior investigator on the study. Credit: Lewis Katz School of Medicine at Temple University

Canola oil is one of the most widely consumed vegetable oils in the world, yet surprisingly little is known about its effects on health. Now, a new study published online December 7 in the journal Scientific Reports by researchers at the Lewis Katz School of Medicine at Temple University (LKSOM) associates the consumption of canola oil in the diet with worsened memory, worsened learning ability and weight gain in mice which model Alzheimer's disease. The study is the first to suggest that canola oil is more harmful than healthful for the brain.

"Canola oil is appealing because it is less expensive than other vegetable oils, and it is advertised as being healthy," explained Domenico Praticò, MD, Professor in the Departments of Pharmacology and Microbiology and Director of the Alzheimer's Center at LKSOM, as well as senior investigator on the study. "Very few studies, however, have examined that claim, especially in terms of the brain."

Curious about how canola oil affects brain function, Dr. Praticò and Elisabetta Lauretti, a graduate student in Dr. Pratico's laboratory at LKSOM and co-author on the new study, focused their work on memory impairment and the formation of amyloid plaques and neurofibrillary tangles in an Alzheimer's disease mouse model. Amyloid plaques and phosphorylated tau, which is responsible for the formation of tau neurofibrillary tangles, contribute to neuronal dysfunction and degeneration and memory loss in Alzheimer's disease. The animal model was designed to recapitulate Alzheimer's in humans, progressing from an asymptomatic phase in early life to full-blown disease in aged animals.

Dr. Praticò and Lauretti had previously used the same mouse model in an investigation of olive oil, the results of which were published earlier in 2017. In that study, they found that Alzheimer mice fed a diet enriched with extra-virgin olive oil had reduced levels of amyloid plaques and phosphorylated tau and experienced memory improvement. For their latest work, they wanted to determine whether canola oil is similarly beneficial for the brain.

The researchers started by dividing the mice into two groups at six months of age, before the animals developed signs of Alzheimer's disease. One group was fed a normal diet, while the other was fed a diet supplemented with the equivalent of about two tablespoons of canola oil daily.

The researchers then assessed the animals at 12 months. One of the first differences observed was in body weight - animals on the canola oil-enriched diet weighed significantly more than mice on the regular diet. Maze tests to assess working memory, short-term memory, and learning ability uncovered additional differences. Most significantly, mice that had consumed canola oil over a period of six months suffered impairments in working memory.

Examination of brain tissue from the two groups of mice revealed that canola oil-treated animals had greatly reduced levels of amyloid beta 1-40. Amyloid beta 1-40 is the more soluble form of the amyloid beta proteins. It generally is considered to serve a beneficial role in the brain and acts as a buffer for the more harmful insoluble form, amyloid beta 1-42.

As a result of decreased amyloid beta 1-40, animals on the canola oil diet further showed increased formation of amyloid plaques in the brain, with neurons engulfed in amyloid beta 1-42. The damage was accompanied by a significant decrease in the number of contacts between neurons, indicative of extensive synapse injury. Synapses, the areas where neurons come into contact with one another, play a central role in memory formation and retrieval.

The findings suggest that long-term consumption of canola oil is not beneficial to brain health. "Even though canola oil is a vegetable oil, we need to be careful before we say that it is healthy," Dr. Praticò said. "Based on the evidence from this study, canola oil should not be thought of as being equivalent to oils with proven health benefits."

The next step is to carry out a study of shorter duration to determine the minimum extent of exposure necessary to produce observable changes in the ratio of amyloid beta 1-42 to 1-40 in the brain and alter synapse connections. A longer study may be warranted in order to determine whether canola oil also eventually impacts tau phosphorylation, since no effects on tau were observed over the six-month exposure period.

"We also want to know whether the negative effects of canola oil are specific for Alzheimer's disease," Dr. Praticò added. "There is a chance that the consumption of canola oil could also affect the onset and course of other neurodegenerative diseases or other forms of dementia."

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User comments

Missing from the report is the fact that canola oil is a GM product as are almost entirely all vegetable oils here in the US. Recall that India formerly had rape oil sellers that made the rounds daily to furnish freshly ground rape seed oil to customers. This is what we call canola here in the US. The demise of the rape seed oil sellers was accompanied by extreme violence against the sellers as to collectively ban these individual sellers and to allow the manufacturing of this vegetable oil in a factory which is then sold on store shelves rancid. There is no way to preserve vegetable oil from rancidity, that is why it was prepared fresh. The rancidity robs vitamins from the blood stream. Odorants and other additives camouflage the rancidity. Note this collectivization also benefits the land owners.

Of course, alternative news and medical reporting websites have been talking about how bad rapeseed (canoloa) oil is for humans, for at least a decade, if not the entire existence (timeline) of the internet.

These are the websites that corporate, government and illiterate levels of power - wish to control or delist from the internet. To make sure that the more accurate reporting of alternative websites is removed from the record and notice.

To use the most bizarre cases of internet data as a flag and case example, to get to the point where they can effectively remove anything that they don't agree with.

Be careful what you ask for, as this point of 'prior art' in discovery in the sciences in the one case, can be magnified at least a few hundredfold in extant alternative medical studies and web reporting.

Of course, alternative news and medical reporting websites have been talking about how bad rapeseed (canoloa) oil is for humans, for at least a decade,...These are the websites that corporate, government and illiterate levels of power

If you would read the paper, you will find that heretofore 'no data are available on the effect that canola oil consumption may have on any of these (neurodegeneration) models and the development of their phenotypes.'. The alternative news sites may have been right, but they arrived at the conclusion without scientific studies.

I hope someone suggests to the researchers that they run two groups: one with GMO canola, and one with organic canola. It is time to investigate this, as GMO is always mentioned as perhaps the main factor, when it may possibly have zero to do with the results.

The warnings that I've seen over the years for canola oil are based on the erucic acid and glucosinolate content of rapeseed. Erucic acid causes damage to heart muscle in some animals. Low Erucic Acid Rapeseed (LEAR), which replaces erucic with oleic acid, was developed for human consumption, though there is no evidence that erucic acid in food harms humans.

The title of this article does not match the results of the study. It is another media/press release misrepresentation of what the authors found. What they found was that in mice made to develop physical neurological pathologies of brain degeneration, those that ate a massive amount of oil and got fat had slight alterations in one of six memory assessments, had less of a protein associated with neural integrity and also had less of one kind of protein found in beta-amyloid plaques, which change their ratios. It does not say anything about Alzheimers in humans, it does not show radical changes in memory. It says that fat mice fed oil for half their lives have slight physiological and behavioral differences. My full critique is published on Medium under Kevin Folta.

Missing from the report is the fact that canola oil is a GM ... rancid. There is no way to preserve vegetable oil from rancidity,... The rancidity robs vitamins from the blood stream. Odorants and other additives camouflage the rancidity. ..

Did you notice that the mice used are "TRIPLE TRANSGENIC"? The mice used were also gmo ... chimeras?

You mention rancid oils; I read long ago about the adverse effects on brain and body are severe. btw--when you process and refine any oil enough it will stay indefinitely--like petroleum fuels.

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